The present invention relates to a gravity biased HVAC duct closure apparatus for a ceiling vent in a structure or building and more particularly, to a counter weighted duct closure system which can be substantially flush mounted against a surface to cooperate with a new or existing HVAC duct system and which automatically opens under the influence of a positive air pressure within the duct, and when the air pressure is negligible, the ceiling vent is automatically sealed by the duct closure via the potential gravity bias of the counter weight to facilitate the retention of treated air previously introduced into the structure or room via the HVAC duct vent.
An objective of the present invention is to provide an automatic duct vent closure to regulate against the backflow of treated air originally introduced to a room through the duct vent to ensure that treated air loss in the form of back flow is kept to a minimum through such a duct vent.
Another object of the present invention is to provide a duct vent closure system which can be easily assembled and installed in combination with either new or pre-existing duct work.
Still another object of the present invention is to provide a duct closure system which is mounted substantially flush with the ceiling so that overhead space within a room is not reduced and the duct vent closure system itself does not impede the flow of air out of the duct or impede the circulation or diffusion of treated air within the structure or room.
Another object of the present invention is to provide an air duct vent closure which is easily removable from the duct vent for maintenance purposes for instance in order to clean the duct vent itself or to clean and wipe free of dust the closure mechanism.
A still further object of the invention is to provide a duct vent closure which breaks up the laminar flow of treated air introduced into the room and causes a desired diffusion of the treated air throughout the room.
Another feature of the invention is the provision of a counterweight attached to and providing a counter balance potential to the door such that when zero positive air pressure is induced in the HVAC duct passageways, the duct vent closure is biased into a closed position by the counterweight such that no air can escape from the room and backflow into the duct passageways.
Another feature of the present invention is that the duct vent closure may be easily removed from the hinging frame apparatus to which it is attached and wiped clean of any dust, dirt or grime which has built up thereupon and then easily put back in place to continue further operation.
This invention relates to a counterweight biased duct closure or door for a conventional overhead or surface mounted forced hot/cool diffuser, vent opening, supply duct or register of an HVAC system, hereinafter referred to as a duct vent. The closure includes a flap or door covering sized to fit over and sealably cover the register or vent opening to insulate the duct passageways from communication with the heated space or air conditioned space when air is not being discharged from the duct and into the room. The duct closure is provided with an extension forming a counterweight to counter balance and influence the door or flap. The counterweight is attached to and spaced from the door or flap about an axis. The door and counterweight are rotatable about a hinge on the axis in response to an increase and decrease of air pressure through the HVAC duct work.
The duct vent closure door and hinge are rotatably secured along a hinge axis to at least a portion of a perimeter frame extending around the periphery of the duct vent opening. The counterweight is spaced from the hinge axis specifically in a direction substantially opposite that of the center of mass of the door in order to provide an opposing force which tends to hold the door sealed and secured against the frame when in the closed position, i.e. when no forced air is being generated by the HVAC system and discharged into the room. Upon generation of forced hot/cold air, a positive air pressure is created in the duct passageways, and the positive air pressure against the door overcomes the sealing bias provided by the counterweight and the covering is automatically pushed open away from the frame of the apparatus, thus enabling the forced air to emanate from the vent and into the room.
The counterbalanced door requires no external power and is designed to automatically seal off and insulate the duct vent opening from the room when the forced hot/cool air and the HVAC fan are off thereby eliminating the ability of treated air escaping back through the registers into an air environment such as an attic or between walls where duct work is commonly routed in many homes and buildings. The frame can be mounted with any conventional attachment means to known vent and register designs, for instance, via magnets or hook and loop closures or conventional bolts or threaded fasteners. The door may remain mounted all year round and can operate during the air conditioning season in conjunction with a forced air conditioning system or a whole house fan, as well as with a heating system during the colder months. The door or closure may also be easily removed and cleaned via a means for detachment to enable cleaning of the vent door.